There has been considerable effort expended in various industries, such as in the paint blasting industry, as to the disposal of the waste products. For example, in paint blasting, the spent blast media normally includes the spent blast media as well as paint chips and the like which often include heavy metals. Because of the presence of the potentially hazardous heavy metals and other spent blast media components, there is considerable government regulation and public interest in the collecting and disposal of such materials.
The present invention has application to numerous processes wherein it is desired to dispose of a waste material containing various materials such as acrylic or urea-formaldehyde plastic materials, and heavy metals and other contaminants. For the purpose of illustration only, the present discussion will make reference to blasting medias, it being understood that all similar waste materials are within the scope of the present invention.
One approach in the art to disposing of spent blast or waste materials has included encapsulating an agglomeration of the waste materials in a suitable plastic coating and then land-filling the coated agglomeration. Presumably the plastic coating is sufficient to prevent migration of the hazardous materials therein or leaching therefrom.
For example, U.S. Pat. No. 4,234,632 discloses a solid waste encapsulation process wherein a solid particulate waste material is coated with a thermosetting resin and then compressed to form a rigid core. The rigid core is then itself encapsulated in a thermoplastic resin to provide a sealed, encapsulated waste agglomerate which can withstand moderate compressive forces. It is important for land-fill operations that the agglomerate be able to withstand compressive forces.
The known processes for encapsulating waste materials, while possibly being sufficient for disposal of the waste material, provides no advantage other than meeting disposal criteria. The hazardous waste material often remains classified by relevant governmental regulations as a hazardous waste not suitable for disposal.
A need exists therefore, for a process and a product which conditions waste materials for a use other than mere disposal. The process and product should condition the waste such that according to current governmental regulations, it is not classified as a hazardous product.